Study Of Preparation And Stability Of High Concentration Liquid Reactive Dyes

Compared with powder dyes liquid dyes have less filling agents in production, have advantages such as lower cost of dyestuff manufacture, the avoidance of dust in handing. On the other side, liquid dyes have good fluid, could improve the solubility of the dyestuff to enhance the stability for preparing ink. One of the key for preparing liquid dyes is to prevent or decrease hydrolysis of the reactive dye in aqueous state to the best of one's abilities, another is to enhance the storage stability by improve the solubility of the dye.In this paper, reactive red K-2BP (C.I.24) was used. First, the properties were carefully investigated, such as solubility, isoelectric range, to find the elementary performances and the optimum pH value after purified the dyestuff. On this base, the effect of the kind and dosage of buffers was investigated through measuring hydrolysis performance of the dyestuff, chose the best one and the best dosage. Next step was to compare the effect of the kind and dosage of organic solvent through measuring solubility performance of the dyestuff, also chose the best ones and best dosage range. Last, preparing orthogonal experiments, determined the compatibility of auxiliaries.The results showed that the hydrolysis and storage stability of liquid dyes reached best when controlled the pH between 7.1 and 7.3. Organic buffer Tris+EDTA-2Na after 24h's heat preservation at 80 centigrade only have a pH variety from 0.2 to 0.3 and 15.6% fixation fall with a dosage of 1%. Organic solvent could improve dye's solubility obviously and enhance dye's weight percent to 15% without wide pH change with about a 20% dosage of organic solvent, these organic solvent include 1,2-propanediol, isopropyl alcohol, polyethylene glycol200, diethylene glycol, triethylene glycol, dimethyl sulfoxide, N,N-dimethyl formamide, caprolactam. Then the best determined were listed as follows: reactive red K-2BP fifteen percent, Tris+EDTA-2Na 1%, isopropyl alcohol 2%, polyethylene glycol200 5%, diethylene glycol 10%, N,N-dimethyl formamide 5%, Tween80 0.5%, distilled water 60.5%. The viscosity is between 5 and 8 mPa·s, surface tension is between 40 and 50 mN/m, electrical conductivity is 2900μs/cm. The liquid dye has a good stability with a pH variety 0.26 and separate dye 0.013g after three months preservation at 25 centigrade.